I would say no. Eels generally prefer softer, more acidic water. Plus, like Lupin pointed out, eels tend to be predatory and often need a diet of frozen or live meaty foods. Cichlids are aggressive feeders and will likely eat this stuff themselves, but African rift lake cichlids really need a diet high in vegetable matter so eating all of that meaty food intended for the eels wouldn't be good for them.

Not to mention that African cichlids tend to be very aggressive and would very likely harass the eels.